pub fn new_birthday_probability(n: u32) -> f64 {
    // TODO: 这里写逻辑
    
    // calculate C(n, 365) / 365^n
    let mut result = 1.0;
    for i in 0..n {
        result *= (365 - i) as f64 / 365.0;
    }
    1.0 - result

}
